Analysis on the prenatal screening results of 7717 cases during the second trimester of pregnancy

Objective:To explore the chromosomal abnormality situations of positive fetuses of trisomy 21 syndrome,trisomy 18 syndrome and neural tube defect in serum screening during the second trimester of pregnancy,carry out secondary diagnosis among high risk population,find the ill fetuses,and prevent their birth.Methods:Time-resolved fluoroimmunoassay was used to calculate the risk values and cut values of trisomy 21 and trisomy 18,then the positive cases received chromosomal karyotype analysis.Results:Among 7 717 cases receiving prenatal screening,295 pregnant women were found with high risk,including 191 cases with trisomy 21 syndrome,the positive rate was 2.48%;32 cases with trisomy 18 syndrome,the positive rate was 0.41%;72 cases with high risk of neural tube defect,the positive rate was 0.93%.Sixty-three positive cases received fetal chromosomal karyotype analysis of amniotic fluid,2 cases with trisomy 21 syndrome and 2 cases with trisomy 18 syndrome were diagnosed definitely;among the cases with neural tube defect,one case with myeloschisis,one case with cleft lip and palate,one case with viscera bareness and two cases with congenital heart disease were diagnosed definitely by ultrasonography.Conclusion:Serum alpha fetoprotein detection and free-β-human chorionic gonadotropin detection during the second trimester of pregnancy can screen out the high risk cases of trisomy 21 syndrome,trisomy 18 syndrome,and neural tube defect,early diagnosis and early intervention can be achieved through prenatal diagnosis.